A502-Switzerland 1983 UPU Service Stamp “Helvetia 120” on First Day Cover Bern

Title:
Switzerland 1983 UPU Service Stamp “Helvetia 120” on First Day Cover – Bern 22 Aug 1983
Category:
Collectibles → Stamps → Europe → Switzerland
Condition:
Used on first day cover (FDC) with clear cancellation, good centering, bright colours, on original envelope. Some light handling marks to envelope; stamp appears fresh.
Item Specifics:
Country/Region of Manufacture: Switzerland
Year of Issue: 1983
Denomination: CHF 1.20 (Helvetia 120) 
Theme: UPU / Universal Postal Union service issue
Format: First Day Cover (FDC) with postal cancel 22 Aug 1983, Bern 3000 
Condition Description: Stamp used on cover, fine, envelope good.
Valuation (estimated):
Since this is a specialized service-stamp issue by the Universal Postal Union (UPU) issued 22 August 1983.  There are few comparable listings; one similar 1983 Swiss UPU FDC lot appeared on eBay.  A conservative estimate for this cover in good condition might be £30–£45.
With premium quality (superb centering, pristine envelope) it might approach £50–£60.
Recommended eBay Listing Price:
£39.99 (Buy It Now) – This provides a competitive price within the estimated range and leaves room for negotiation or offers.
Auction Option:
Start the auction at £19.99, no reserve, for a 5-7 day duration. Add “Buy It Now” at £39.99 to allow immediate purchase.
Additional Notes for Description:
Mention that this is a service labelled “Timbre-poste de service de l’Union postale universelle” issued by Switzerland.
Note clear cancellation “3000 Bern 15 / 22.8.1983”.
Emphasise the collectible appeal: UPU thematic, Swiss modern issue, FDC.
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