Mr Allanson was found already dead.
It is understood the killer fled through the 71-year-old’s back garden. A man was arrested a short time later.
Residents heard police officers repeating the name of a suspect on a walkie-talkie while at the scene, detailing an address for colleagues to immediately visit.
Friend Mrs Taylor said: “He’d not long come back from a holiday in Tunisia and had booked to go again in the summer.
“I worked with him at Birkenhead Indoor Market where he was on the fruit and veg and I was on the sweets.
“Many years ago, he was involved in an accident on a fishing trawler that took his leg off.
“Bert was funny and well-liked. If it was anyone’s birthday, he’d put a card through the door for them. We just can’t believe this has happened.”
Mr Allanson, who formerly ran a greengrocer’s on Duke Street, lived alone and had been in his Dawson Avenue home for over two decades. He has a sister and brother, also from Wirral.
Floral tributes were left outside their house, and one said: “To Mr Bert, gone but never forgotten. Hopefully in a summer place looking after God’s garden.’
Detectives have charged Dean Brennan, 20, of Laird Street, Birkenhead, with murder and robbery. He was appearing before Wirral magistrates this morning.